1. Field of the Invention
The present invention relates generally to optical fibers and optical fiber connectors, and more specifically to methods for centering one or more optical fibers in an optical fiber connector ferrule.
2. Technical Background of the Invention
With the ever growing demand for lower loss fiber optic connections, the centering of one or more optical fibers in a ferrule of an optical fiber connector is becoming more and more critical. The ideal position of an optical fiber in a ferrule bore is the “dead center” of the ferrule bore—i.e., the optical fiber centerline is exactly aligned with the bore central axis. However, achieving such exact alignment has proven to be difficult. Also, with the introduction of bend insensitive fibers, it is preferred that the holes, voids or “airlines” within the optical fiber be closed off at the point where two fibers connect—namely, at or near the end of the ferrule—to prevent contaminants from gathering in the exposed airlines and adversely impacting the transmission of light between the connected optical fibers. The voids can include a gas such as Nitrogen or Krypton, or a mixture of such gases, such as air, Nitrogen, and/or Krypton.
One reason why centering one or more optical fibers in a single-fiber or multi-fiber connector ferrule is difficult is because it is not practical to use an interference fit between an optical fiber and a ferrule bore. Optical fibers can vary in size by up to ±1 micron or so, so that sizing a ferrule bore to have an interference fit with the optical fiber would result in significant amounts of optical fiber not fitting into the bore. In addition, those optical fibers that can barely be fit into the bore have a higher risk of being damaged due to the tight fit. In addition, an optical fiber is typically secured within the ferrule bore using an epoxy, so that some space within the bore must be maintained to accommodate the epoxy.
Once an optical fiber is exactly aligned in the ferrule bore, it must be locked into place. It is therefore important to have a simple and efficient way of maintaining the optical fiber in its centered position within the bore until the epoxy curing process or other fixing process can be carried out.